OE THE UNITED STATES 25 



In a naturalist's armamentarium there are two sets of things 

 which are co-equal in importance to him, and both essential to 

 his success. These are his implements upon the one hand, and 

 his books upon the other. His microscope and its appurte- 

 nances; his guns and their belongings; his camera and its outfit; 

 his drawing and coloring utensils; his other and many various 

 instruments of precision — may be considered to be the active 

 agents in his researches, while his library is the passive one. By 

 the means of the first he obtains, studies, dissects, and makes 

 descriptive record of material, while by the use of the second he 

 compares the observations of others in every possible way; de- 

 tects errors; ascertains the limitation of knowledge upon any 

 particular point or subject; and finally, establishes in his mind 

 the relative value of his observations, and exactly, in the event 

 of their being published, to what extent they may be considered 

 a contribution to the particular line of biological research along 

 which they have been made. 



Both books and implements should be of the very best obtain- 

 able: the first in the matter of recognized authority, and the 

 second with regard to manufacture. The best test for the acqui- 

 sition of either is the appreciation of the feeling for its need. 

 Purchase only as the demand presses, and as the widening of 

 your field requires it. Excess of either tools or volumes can but 

 create lumber in the laboratory; demand care without the ade- 

 quate increase in efficiency; and levy a pecuniary tax, which 

 might have been used with greater power in some other direction. 



In the matter of books, again, the naturalist will of course be 

 greatly influenced by circumstances. If he has access to very 

 extensive scientific public libraries, he needs at hand, of his 

 own, only such works of reference as his researches require. 

 These may be limited in some cases to text-books, practical 

 works upon the use of instruments and dissections; compen- 

 diums, keys, manuals, lexicons, and the like, with perhaps some 

 fifty volumes upon the general literature of his science. A dozen 

 or more good journals and magazines should likewise find their 

 way to his study table. 



Eight times out of ten, I find no difficulty in entering my li- 

 brary and work-room in the dark, and finding the volume I need, 

 or placing my hand upon any implement required. Precision, 

 extreme neatness and order, economy in time carried to the 

 maximum, and the minimum use of appliances compatible with 



